Grinding aid

Abstract

This invention relates to organically bonded abrasive articles that include grinding aids. It has been determined that when known grinding aids such as alkali metal sulphates and alkali metal chlorides are cofused in about eutectic proportions and added to thermoset resin bonded abrasive articles in the form of finely crushed particles having an approximate eutectic composition that an improved abrasive article results.

We claim: 
     
       1. An abrasive article comprising abrasive grain and a bonding material, said bonding material being a thermoset binder resin and said article including a grinding aid filler, said filler consisting of a cofused near eutectic mix of an alkali metal sulphate and an alkali metal chloride, said mix being crushed prior to being included in said mix. 
     
     
       2. An abrasive article as in claim 1 wherein said alkali metal sulphate is potassium sulphate. 
     
     
       3. An abrasive article as in claim 1 wherein said alkali metal chloride is sodium chloride. 
     
     
       4. An abrasive article as in claim 2 wherein said alkali metal chloride is sodium chloride. 
     
     
       5. An abrasive article as in claim 4 wherein said alkali metal sulphate is present in about 60% by weight and said alkali metal chloride is present in about 40% by weight. 
     
     
       6. An abrasive article as in claim 1 wherein said mix is crushed to all pass through a 200 mesh U.S. Standard screen. 
     
     
       7. A bonded abrasive article comprising an organic bond for abrasive grains and including a grinding aid filler, said filler consisting of a cofused and crushed mixture of an alkali metal sulphate and an alkali metal chloride, said respective alkali metal salts being present in said mixture in a near eutectic proportion. 
     
     
       8. An abrasive article as in claim 7 wherein said alkali metal sulfate is potassium sulphate present in about 60% by weight of said mixture, and alkali metal chloride is sodium chloride present in about 40% by weight of said mixture. 
     
     
       9. A raw batch for making an abrasive grinding article comprising a resin bond formula adapted to be thermoset, abrasive grain, and filler material, certain of said filler material consisting of a near eutectic composition made of an alkali metal sulphate and an alkali metal chloride, said composition being a cofused and crushed composition. 
     
     
       10. A raw batch as in claim 9 wherein said composition is crushed to pass through a 200 mesh U.S. Standard screen. 
     
     
       11. A raw batch as in claim 9 wherein said alkali metal sulphate is present in said composition in about 60% by weight and said alkali metal chloride is present in about 40% by weight. 
     
     
       12. A method of grinding metal with an organically bonded abrasive grinding wheel comprising driving the thermoset resin supported abrasive against the metal being ground in the presence of a grinding aid consisting at least in part of a cofused crushed nearly eutectic composition of an alkali metal sulphate and an alkali metal chloride. 
     
     
       13. A method as in claim 12 wherein the alkali metal sulphate is potassium sulphate. 
     
     
       14. A method as in claim 12 wherein the alkali metal chloride is sodium chloride. 
     
     
       15. A method as in claim 13 wherein the alkali metal chloride is sodium chloride.